Putty knife



June 3, 1941.

R. W. OLIVER PUITY KNIFE Filed June 7, 1938 INVENTOR; 2205a): Wafiace aid/e2 ATTORNEY.

Patented June 3, 1941 UNITED STATES PATENT OFFICE PUTTY Robert Wallace Oliver, Syracuse, N. Y.

Application June 7, 1938, Serial No. 212,348

(01. run-3.5)

Claims.

My invention relates to a putty knife or applying tool for applying and trimming putty or similar plastic substances to grooves, edges or corners or other locations.

The putty knife heretofore used has been a thin flat piece of steel of substantially uniform thickness and terminating in a perpendicular straight edge. Such a putty knife is recognized as having various shortcomings, including the inability to satisfactorily work in corners, the production of only a straight-edge boundary of the laid-up putty, the frequent necessity of using a different knife for trimming than is used for applying, the necessity for maintaining a substantially fixed orientation of the blade as it is being moved along the putty, the creeping of putty up on the handle of the knife, the impact of the sharp edge of the blade on the thumb when pushed up on the side of the blade, and

the adherence to the blade of putty at points where it can not be usefully used for applying.

It is an object of my invention to provide a putty knife that has curvilinear contours for its several applying surfaces.

Anotherobject of my invention is to provide a single all-purpose putty knife that will efiiciently both apply and trim in all locations ordinarily met in practice.

A further object of my invention is to provide a putty knife having a blade whose lateral edge is relatively sharp on its forward portion near the point of the knife for trimming, and whose lateral edge is relatively blunt on the rearward portion of the blade where the thumb is usually applied to the blade.

Still another object of my invention is to provide a putty knife of a shape adapted to fit into corners and grooves of unusual shapes, and into a wide range of angles between a pane of glass and a window frame.

Yet another object of my invention is to provide a putty knife to which putty when removed from a box will adhere for the most part only to those portions of the knife which are useful for applying.

Another object of my invention is to provide a putty knife which will lay up a relatively large amount of putty per stroke.

A further object of my invention is to provide a putty knife which will dish out or make concave the exposed surface of the putty laid up.

A still further object of my invention is to provide a putty knife having applying surfaces of respective curvilinearities which are so related that the orientation of the knife as moved forward in applying may be successively varied while continuing the curved contour of the applied putty without abrupt change.

I have in my experiments tried many different forms of putty knives in efforts to find a form best adapted for the ordinary purposes, and the form herein described has by me been found most satisfactory.

The terminal blade portion of my knife may be in a general way referred to as a modified flattened ellipsoid with relatively sharp edges, and the blade contracts to a neck portion and then flares out to a terminal shoulder for the tang. The terminal portion of my, blade has 'a certain general resemblance to a duckbill.

Heretofore there have been known certain socalled spoon shaped putty knives, but they have had undesirable contours and for the most part have been fiat with uniform thickness, and unsatisfactory and incapable of producing the results attainable with my putty knife.

My invention will be better understood by reference to the following specification and the accompanying drawing wherein like characters of reference represent corresponding parts throughout the several views, and wherein: V

Figure 1 is a plan view of the putty knife with handle showing the curved contour of the applying terminal portion of the blade;

Figure 2 is a side elevation showing the tapering of the blade, and the handle structure;

Figure 3 is a longitudinal sectional view taken on the line 3-3 of Figure 1;

Figure 4 is an end elevation of the applying end of the blade;

Figure 5 is a transverse sectional View taken on the line 55 of Figure 1;

Figure 6 is a transverse sectional view taken on the line 6--6 of Figure 1;

Figure 7 is a transverse sectional view taken on the line 1'! of Figure 1;

Figure 8 is an enlarged plan view of the blade showing in dotted lines the construction lines of the curvilinear contour of the blade;

Figure 9 shows the use of my putty knife in applying putty in a corner against a glass pane in a window frame;

Figure 10 is another View of a mode of using my putty knife to set glass in a frame;

Figure 11 shows the dished contour of the putty applied by my knife, as compared with the straight-edge boundary obtained with an old fashioned straight-edge knife;

Figure 12 shows the modes of using my knife in different angular orientations both in applying and in trimming on a pane in a window frame; and

Figure 13 is a transverse sectional view taken on the line l'3l3 of Figure 1.

My putty knife may be made of steel, brass, or other metals or alloys of suitable characteristics which avoid excessive brittleness or softness.

Referring to the figures in detail, the knife as a whole is shown at I having a blade portion 2, and a tang 3 for the handle. Handle pieces i of food or fiber or the like are mounted on tang 3 by rivets 5. In Figure 1, just to the left and toward the point of the blade from the edge of wooden handle piece 4, the metal blade rises to a shoulder as shown at B, which shoulder is of the same thickness and flush with the outer sides of the handle. The handle has a rounded end as shown at l. 1

In a knife which I have constructedand used very successfully for ordinary practical purposes,

the overall length from point of blade to end of handle is five and three-quarters inches, and the length from tip of blade to the edge of the shank where the wooden handle 4 begins, just to the right of shoulder 6 in Fig. 1, is two and one-half inches. The maximum width of the blade as measured at hit in Figure 1, is 0.93 inch. The thickness of the blade at hk, or approximately at the line a:r in Fig. 2, is about nine thirty-seconds of an inch, and this thickness does not increase appreciably in passing to the right in Fig. 2 toward the shoulder 6 until the neck portion is reached which is shown at il. As shown in Fig. 2, the thickness of the blade flares out passing from neck at iZ' to the shoulder at 5. The tang 3 has a thickness of about one-eighth inch.

As shown in Figures 1 and 8, the lateral contour of the blade 2 is curvilinear, and as particularly clearly shown in Figure 8, the terminal portion of blade 2 for the most part has a lateral contour which is elliptical. In Figure 8, the longitudinal axis of the blade is shown at gt and passes through the point 9 of the blade, and is an axis of symmetry of the blade. As will also be seen in Figure 8, the lateral contour of blade 2 from point 9 to an appreciable distance back from the maximum width of the blade, is an ellipse shown in Fig. 8 at ghqlc, having major axis ya and minor axis hie. Backward of the point where the lateral contour of the blade departs from the ellipse ghqlc, the lateral contour of the blade continues to curve with-out inflection to :a relatively narrow neck portion shown at 2'1, and there inflects and flares out to the shoulder 6. The shoulder is fiat for a short distance and then forms .a shank against which the wooden handle pieces 4 abut.

The point 9 of blade 2 is relatively sharp, and the lateral edge of the bladeis relatively sharp on both sides back about as far as the maximum width of the blade at hk, the sharp point and sharp portion of the lateral edge are very useful for trimming putty which has been laid up. Backward from the points hk to the neck z'l the lateral edge of the blade becomes relativelyblunt,

line hk of maximum width, the blade 2 tapers icurvedly, convexly, so as to form a convex applying surface of the blade from g to at. The slope of this tapered portion measured as a straight line may be about one on four to one on five.

In the particular form shown in Figure 8, the ellipse ghqk has a ratio of major axis to minor axis of about 1.6, which ratio I find to give very good results. However, other ratios of major to minor axis are also suitable and within the spirit of my invention, within a range of say from 1.25 to 2.0, although the extremes of this range do not give as satisfactory results as does the ratio of 1.6 here particularly set forth. The optimum ratio of about 1.6 may be said to be fairly critical. Other values of this ratio'within the range 1.25 to 2.0 give fairly satisfactory results.

The actual dimensions which I have mentioned are found to be suitable for ordinary work, but it will be understood that such dimensions are given only as an illustrative example. For special conditions, the dimensions of my knife can be increased or diminished in approximately constant ratio, and substantially the same results ob tained.

Besides the ratio of major to minor axis, the ratics of other dimensions such as the slope of thickness taper back from the point, may be varied within a reasonable range of say 25 percent increase or decrease, and retaining results comparable with the optimum ratios of dimensions here set forth.

While I have described the lateral contour hole as elliptical, it will be realized that other curves may be made to very closely approximate the curve shown as hglc; thus a parabola may be made to very closely superimpose on the curve hglc shown, as may fitted arcs of three or more circles. While I describe the lateral contour being substantially elliptical, it will be realized that minor departures from a strict ellipse 'to other curves close to an ellipse are within the spirit of my invention. Thus a lemnisoate will closely approximate the type of curve which I employ.

The successive changes in the sharpness of the lateral edge .of the blade are shown in the figures. The point itself is relatively sharp, and just back thereof, as shown in Fig. 7, the edges ye are sharp. Likewise at hk, as shown in Fig. 5, the

lateral edges are sharp. In Fig. 13, at mn, the lateral edges have become somewhat blunt, and at the neck iZ, as shown in Fig. 6, the edges have entirely flattened out. As previously explained, just backwards of points his, the lateral edges be come sumciently blunt so that the thumb of the operator may be advanced on the edge without discomfort. i

I find that one important feature of my invention is that the thickness, taper starts at the point of maximum width, which is found to give particularly good results.

I have experimented with a putty knife having a lateral contour of the blade substantially like.

timum form of blade which I have described; Also I have tried a blade wherein the curvaw.

tures of the lateral edges form a terminal point which is decidedly'sh'arpened as compared with the smooth elliptical :curve which I show in Fig. 1 passing through point g. and I find that such sharp pointed blade is less satisfactory than the blade which I show in Fig. 1.

A knife having an applying end which is semicircular will not allow the knife to miter int-o corners and remove and trim out the proper amount of putty.

The blade 2 and tang 3 are advantageously made as a single casting.

In my blade, the width his is relatively large compared with other so-called spoon blades which have been tried, and therefore my blade applies more putty per stroke than do such other blades. On the other hand I find that if the blade is made too wide, it is ineffective for proper application of putty.

I make my knife with the lateral edge (as gkl) of the correct sharpness to most successfully trim and miter the putty without cutting or digging into the wooden sash or window frame. Such cutting and digging are recognized as important faults of the present straight flat type of putty knife.

The fact that the point g of the blade is made relatively sharp as to thickness, and that the lateral edge forward approximately of points his is sharp, causes my putty knife to satisfactorily trim the putty to the pane and the window frame, and also to satisfactorily miter in corners, without rigorous requirement as to knife position.

The unsatisfactory early experimental form of blade which I have mentioned with substantially uniform thickness was not thick enough at the point of maximum width and could not easily produce a good bevel of laid up putty from glass to window, and the exposed surface of the putty as it did produce it, was not dished out enough.

In Figure 9 there is shown the mode of using my putty knife blade 2 to apply putty lfi against the window pane 9 and the edge E2 of the window casing 8. The concave contour of the laid-up putty H) as laid up by my knife is clearly shown. In Fig. 9 the breadth of the blade is held perpendicular to the direction of movement of the blade along the edge to which putty is being applied.

In Fig. 10 there is shown the employment of my knife in laying up putty with the breadth of the blade parallel to the direction of movement of the blade as it is pushed along the edge to which putty is being applied. The concave contour of the laid-up putty IE is also shown in Fig. 10, but since the relatively flat part of the curved surface of the blade 2 is doing the applying, this concaveness is less in degree than in Fig. 9. In Fig. 10 there is also shown the manner in which surplus putty shown at I I drips off at the neck z'Z of the blade, as the putty is trimmed with the knife.

I find that the narrow neck il of the blade is also very useful in removing putty from the box for application, since little putty will adhere back of this neck, and the quantity takenout at one time is fairly uniform. Also, in applying, I find that the neck 21 is very useful as substantially preventing putty from working back from the applying part of the blade, up on to the handle, which impedes the use of the knife by the operator.

The particular curvature which I show for my blade may be said to stream-line the blade, and in any event it greatly diminishes the amount of putty which adheres to the blade at points on the blade where it can not be usefully applied to the work.

In Fig. 11 I have shown putty H) as laid up between pane 9 and edge l2 of casing 8, the contour acb of the laid up putty being dished out or concave. For comparison I have also shown in Fig. 11 the straight-line exposed edge of the laid-up putty as it would be laid up by the usual straight-edge present putty knife. One advantage of the dished-out exposed surface is that it results in causing the central or thickest portion of the laid-up putty to more closely approximate uniformity of thickness. This materially decreases the probability of checking or cracking of the putty when laid up, in the course of time. This is true whether the depth of the putty is one-fourth inch, which is usual practice, or is greater, as one inch. Also, with the dishedout exposed surface produced with my knife, an appreciable quantity of putty is saved.

In Fig. 12 I have shown two successive positions of my putty knife in use on a frame. At A, I have shown my knife being used for applying putty, in the position of Fig. 10, the knife being in a plane substantially perpendicular to the edge against which putty is being applied.

In Fig. 12 at B, I have shown my knife being used to trim putty off to produce a result as in Fig. ll, the knife being held at an angle of say 30 to 45 degrees, shown as angle w in Fig. 12, with the edge to which putty is being applied. This angle is varied to fit different bevels.

To produce the final contour shown in Fig. 11, the blade is tilted at an angle of say 45 degrees so that the edge rather than the fiat surface of the blade fits the contour of the curved bevel.

In the blade which I describe, the thickness-of the blade at the center and the curvature toward the sides as it slopes down to the edge, results in a blade that will adapt itself to almost any angle between pane and frame that a glazier may have to fill with putty. With my blade, it is possible to hold the blade in such a position as to produce an exposed putty surface which closely approximates a straight line, making either a large or small acute angle with the pane, if such an exposed surface is desired.

For various points on the lateral contour of my blade, the radius of curvature is about the same as the radius of curvature of the relatively flattened surface of the blade over the tapered portion.

While it is possible to produce with my blade an approximately straight-line exposed surface, it is usual to hold the knife in such a position as to produce a more or less dished exposed putty surface, with the resultant advantages above mentioned.

By having a curvilinear contour of both the lateral contour boundary of the blade, and the thickness contour, it is possible to twist my knife into successive angular orientations and still obtain a curvilinear dishing of the exposed putty surface, with curvatures which gradually change from one curvature to another and get any kind of curvature desired. This result is not possible with a blade of uniform thickness and having no curving of the relatively fiat face of the blade. Also, the old conventional type of putty knife tapers very sharply to a point as to its thickness, such taper existing only over a length of say an eighth of an inch, producing an angle of 45 degrees or more, and with such a sharp thickness taper it is impossible to obtain any such type of curves or gradual changes of curves of laid-up putty as may be obtained with my knife.

In an efiort to obtain results of the type which are attainable with the curved applying surfaces of my blade, glaziers sometimes use their thumbs to mould the putty, which practice is in every respect unsatisfactory.

The sharp point of my blade cuts the putty edge against the glass as in the position shown in Fig. 10, and the sharp edge of the blade back as far as points hlc at maximum width, trims the edge of the putty out on the casing edge.

My knife is adaptable to efficient performance of the various operations necessary to glaze or set a window in putty, and a single knife as described by me will perform the operations for which several tools would otherwise be required.

By employing my improved form of putty knife, it is possible to save half or more of the time which would be required to bed and finish a pane of glass with a conventional form of putty knife. There is a substantial saving in the amount of putty required for a given job. My knife is far more adaptable to unusual conditions than the conventional putty knife now used.

While I have described the employment of my knife and its characteristics primarily with reference to laying up putty, it will be understood that my knife is well adapted and very efiicient for laying up and moulding other plastic substances, such as cements, plasters, and the like.

It will be obvious that I have produced a putty knife which is simple to manufacture and very effective in use. To those skilled in the art, it will be obvious that my invention is susceptible of various minor modifications to meet some particular condition, and all such modifications as come within the scope of the appended claims I consider to be comprehended within my invention.

I claim:

1. A putty knife having a free terminal applying portion of its blade whose lateral contour is substantially a part of an ellipse, said part being symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6.

2. A putty knife having a terminal applying portion of its blade whose lateral contour is substantially a part of an ellipse, said part being i,

symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered relatively gradually in thickness backwards from a terminal free applying point thereof.

3. A putty knife having a terminal applying portion of its blade whose lateral contour is substantially a part of an ellipse, said part being symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered in thickness backwards from a terminal free applying point thereof with a slope of between about one on four to one on five.

i. A putty knife having a blade whose lateral contour is substantially a major fractional part of an ellipse terminating in a free terminal applying point, said part being symmetrical about the major axis of the ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said lateral contour being continued in the direction away from said applying point as curves converging to a narrowneck portion and thereafter curvedly diverging to form a shoulder.

' 5. A putty knife havinga terminal applying portion of its blade whose lateral contour is sub? stantially a part ofan ellipse, said part being symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered in thickness backwards from a terminal freeapplying point thereof substantially to the point of maximum width of the blade, with a slope of between about one on four to one on five.

6. A putty knife having a terminal applying portion of its blade whose lateral contour is substantially a part of an ellipse, said part being symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered in thickness backwards from a terminal free applying point thereof substantially to the point of maximum width of the blade with a slope of between about one on four toone on five, and said blade continuing with substantially uniform thickness further backwards of said point of maximum width nearly the full length of said blade.

'7. A putty knife having a blade whose lateral contour is substantially a major fractional part of an ellipse terminating in a free terminal applying point, said part being symmetrical about the major axis of the ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said lateral contour being continued in the direction away from said applying point as curves converging to a narrow neck portion and thereafter curvedly diverging to form a shoulder,

. the terminal applying portion of said blade being tapered in thickness backwards from a terminal free applying point thereof substantially .to the point of maximum width of the blade with a slope of between about one on four to one on five.

8. A putty knife having a blade whose lateral contour is substantially a major fractional part of an ellipse terminating in a free terminal applying point, said part being symmetrical about the major axis of the ellipse; said ellipse having a ratio of major'axis to minor axis of substantially 1;6, said lateral contour being continued in the direction away from said applying point as curves converging to a narrow neck portion and thereafter curvedly diverging to form a shoulder, the terminal applying portion of said blade being tapered in thickness backwards from a terminal free applying point thereof substantially to the point of maximum width of the blade with aslope of between about one on four to one on five, and said blade continuing with substantially uniform thickness further backwards of said point of maximum width substantially to the point of minimum width of said neck portion.

9. A putty knife having a terminal applying portion of its blade whose lateral contour is substantially a part of an ellipse, said part being symmetrical about the major axis of said ellipse, said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered inthickness backwards from a terminal free applying point thereof with a slope of between about one on four to one'on five, and

further tapering convexly curvedly away from stantially a part of an ellipse, said part being symmetrical about the major axis of said ellipse,

said ellipse having a ratio of major axis to minor axis of substantially 1.6, said applying portion being tapered relatively gradually in thickness backwards from a terminal free applying point thereof, and further tapering convexly curvedly 

